Mental health expert and Australian of the Year Professor Patrick McGorry is leading calls for the Federal Government to commit more money to the country's mental health system.

At a candlelight vigil in Melbourne last night, he told a crowd of hundreds the peak onset for mental illness is adolescence and early adulthood, which is why more early intervention for youth is desperately needed.

He said Labor's $277 million plan is simply not enough and the Coalition's $1.5 billion proposal may have a better price tag and a focus on youth, but it excludes children and older people.

"We have to ask the Prime Minister, how is this commitment going to be realised if there is not a financial investment allocated to support it? Is it going to come out of thin air?" he said.

But Professor McGorry says the building blocks are already there and all that is needed is the money and the commitment.

"The fundamentals are already there. The Health and Hospitals Reform Commission has laid out 12 recommendations which are being looked at very, very carefully and offer a blueprint for a way forward which could be invested in tomorrow," he said.

Political campaign group GetUp organised last night's vigil outside the International Youth Mental Health Conference.

National director Simon Sheikh said the groundswell of support for GetUp's national mental health campaign is unprecedented.

"Just a few months ago an extraordinary thing happened to GetUp - 75,000 people in a matter of four days joined our mental health campaign," he said.

"[It's] an amazing number and... never in our history... have we seen a campaign grow as quickly as this mental health campaign."